The present invention is directed to a method for containing spent nuclear fuel rods in protective containers so as to facilitate disposal of the fuel rods.
U.S. Pat. application Ser. No. 860,557 now U.S. Pat. No. 4,209,420 describes how used or spent nuclear fuel rods can be contained in protective containers for final disposal of the spent fuel rods, the containers preferably being placed in rock cavities or other spaces below the ground surface.
Nuclear fuel rods have substantial lengths, usually about 4 meters. It is desirable to limit the length of protective containers for these rods to less than the length of the rods due to the considerations of the manufacture of the ceramic protective containers, reduction in stresses in handling the protective containers and minimizing damage to the containers in case of movements in rock after disposal.
One solution is to cut the fuel rods into shorter lengths. This solution, however, leads to the disappearance of the protective barrier on the fuel rods. Thus, gaseous fission products contained in the cladding tubes of the rods must be taken care of in a safe manner. In addition, the risk of the spread of fission products formed during storage is also increased.
Another solution is to bend the fuel rods prior to containment. However, the cladding material of the rods has insufficient ductility to completely avoid fractures and therefore fission products may be released. Thus, this solution also necessitates measures for taking care of the fission products.